Red ring with 3 alpha-numeric code [letter/number/letter] (on one) leg and metal ring (on other leg).
note 1 : used codes are : A00-A99, B00-B99, C00-C99, D00-D99, F00-F99, H00-H99, J00-J99, K00-K99, L00-L99, N00-N99, P00-P99, S00-S99, Y00-Y99.
note 2 : this study concerns the migration of Lesser Kestrel in Italy.
note 3 :